BONUS vz.85

Due to the limited strength and brittleness of the standard assault knife UTON vz.75, which no longer met demanding conditions during operations behind enemy lines, a new Combat Knife Universal Special — abbreviated BONUS was designed.

Development of the knife began in 1985. Subsequent field tests with reconnaissance units demonstrated its high readiness during parachute jumps, effectiveness in close combat and wide multi-purpose use behind enemy lines. The knife was intended for units of tactical, deep and special reconnaissance of the ČSLA as a personal weapon and robust working tool.

Due to its construction and quality of materials, it excelled in stabbing, cutting and chopping tests, significantly surpassing the UTON then in use. Tests included: piercing a 15–20 mm wooden board with one blow, piercing a 3 mm plastic board or thin sheet metal up to 1 mm. When chopping, it cut through hard plastic up to 5 mm, wire up to 3 mm, aluminum sheet up to 15 mm, or severed a 20 mm cable on a surface.

A major advantage was its durability — thanks to its massive pommel it could be used as a chisel and punch holes in iron sheet up to 1 mm without damage. The strength was extraordinary — in tests it withstood 15 kg of prying force without any deformation or breakage.

A series exceeding 6,000 pieces was planned in total, with each piece priced at 245 CZK at the time. Production was handled by Aquacentrum Praha.